August 15th - Maury Ginsberg hitches a lift to the Woodstockmusic festival in New York on Earth. He notices that a cable connecting to the speaker system has come unplugged and reconnects it. If he had not noticed, the festival might have been a failure. He is not aware that the man who drives him there is the member of the Q Continuum later known as Quinn. (VOY: "Death Wish")

This assumes the fault is found before the festival as a whole begins.